Storage and retrieval of objects is a process that is carried out in many ways for many purposes. A specific use of storage and retrieval, namely, order-fulfillment, is a core process performed within virtually all supply chains, especially retail supply chains. Manufacturers generally store and retrieve pallets containing cases of products within their distributions to fill orders for products placed by retailers. Retailers store and retrieve both the cases and the individual product items, or “caches”, within their own distribution centers in order to fill orders placed by their stores for case-quantities and less-than-case quantities of products. Increasingly, with the rise of e-commerce, retailers are also faced with the necessity of filling orders for caches placed directly by individual consumers.
Conventional order-fulfillment processes within retail distribution centers use manual storage and retrieval systems and methods in which cases or totes containing eaches are stored in stationary locations and human pickers move to selected locations to pick ordered cases or eaches, respectively. However, the labor efficiency of such “picker-to-goods” processes is typically quite low because the pickers spend much more time traveling to the locations than actually picking the ordered items.
The most successful solutions for improving labor efficiency in order-fulfillment processes use some form of automated storage and retrieval system and method in a “goods-to-picker” process in which the containers are delivered by mechanized means to a workstation, where a picker (human or robotic) either places the cases on pallets for delivery to stores or transfers eaches from the product containers to order containers for delivery to stores or individual customers.